For an existing in-cell touch panel, touch driving electrodes and touch sensing electrodes are arranged within a cell of a liquid crystal display (LCD). To be specific, an entire indium tin oxide (ITO) layer having a common electrode voltage Vcom is divided into two parts, one serving as common electrodes, and the other being multiplexed as common electrodes and the touch driving electrodes. Each touch sensing electrode is arranged at a horizontal black matrix (BM) region on a color filter substrate corresponding to the ITO layer.
The existing in-cell touch panel includes a plurality of gate lines arranged horizontally, a plurality of touch driving electrodes arranged longitudinally, and common electrodes. Each touch driving electrode includes a plurality of touch driving sub-electrodes arranged longitudinally, and each common electrode is located between two adjacent rows of the touch driving sub-electrodes. Each touch driving sub-electrode and each common electrode cross P gate lines, and P is a positive integer. The plurality of touch driving sub-electrodes of each touch driving electrode are connected in series to each other, and connected to a corresponding touch driving signal line. In addition, all the common electrodes of the existing in-cell touch panel are connected to a common electrode line (Vcom line).
Referring to FIG. 1, which is a sequence diagram of the existing in-cell touch panel for achieving an image display function and a touch function, the existing in-cell touch panel is driven in a time-division manner.
In FIG. 1, V-sync represents a sequence signal. To be specific, the existing in-cell touch panel includes n gate lines, e.g., gate line 1 (Gate 1), gate line 2 (Gate 2), . . . , gate line m (Gate m), gate line m+1 (Gate m+1), gate line m+2 (Gate m+2), gate line m+3 (Gate m+3), . . . , gate line n−1 (Gate n−1) and gate line n (Gate n), data lines Data, the touch driving electrodes Tx (T1, T2, . . . , Tn), and the touch sensing electrodes Rx (R1, R2, . . . , Rm). m and n are both positive integers.
In FIG. 1, in a first time period of 12.7 ms within one frame, a gate voltage is applied onto the gate lines sequentially, a data signal is applied to the data lines sequentially, and a constant voltage (a common electrode voltage) is applied to the common electrodes (including the touch driving electrodes that are multiplexed as the common electrodes) sequentially, so as to display an image. In a last time period of 4 ms within the frame, a low level signal is applied to the gate lines and the data lines so as to turn off thin film transistors (TFTs) connected to the gate lines. In addition, a corresponding touch driving voltage is applied to the multiplexed touch driving electrodes sequentially, and the constant voltage is applied to the touch sensing electrodes. At this time, an electric field is generated between the touch sensing electrodes with the constant voltage and the touch driving electrodes with the touch driving voltage, so as to achieve the touch function. The display driving and the touch driving are performed by the existing in-cell touch panel in a time-division manner within one frame, so the time for the touch driving is limited and a touch response speed is low.